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Sildenafil Non-Responders: Haemodynamic and Morphometric Studies

Eric Wespes E, Rammal A, Garbar C; European Urology 2005 (48):136-139

KEY WORDS: Erectile dysfunction; PDE5 inhibitor; Sildenafil non-responder; Impotence

Erectile dysfunction (ED) is often associated with a cluster of risk factors for coronary artery disease and reduced endothelial function. Acute and chronic administration of oral sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, improves endothelial function in patients with ED. Tadalafil (TAD) is a new PDE5 inhibitor with a long half life that allows alternate day administration. Aim of the study was to evaluate whether chronic therapy (4 weeks) with TAD improves endothelial function in patients with increased cardiovascular risk and whether this effect is sustained after discontinuation of therapy.

• A total of 30 patients with ED aged from 28 to 74 years-old did not respond to 8 attempts of 100 mg of sildenafil. They underwent hormonal measurements, intracavernous injection (ICI 20 mg PgE1) followed by Doppler examination and cavernosometry. A penile biopsy was performed under local anesthesia. A quantification of the cavernous smooth muscle (SMC) was performed with a computerized image analysis after staining with actin anti-actin.
• Severe vascular lesions and atrophy of SMC are mainly observed in sildenafil non-responders. The age, diabetes and low testosterone level seem not to be related with the failures. Patients with cavernovenous leakage as pure or mixed vasculogenic erectile dysfunction have lower Patients with severe vascular lesions and reduction of intracavernous smooth muscle cells are poor candidates for sildenafil therapy. However, the same study should be performed in sildenafil responders. Caution for sildenafil initiation treatment should be taken with patient with very poor erectile response after PGE1 intracavernous injection.

See the abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15967263&dopt=Citation